Methyl iodide → HCID 54535345, compound

Participants

Reaction Steps

To a stirred solution of 1.00 gram (0.0024 mole) of 5-amino-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-methylsulfinyl-1H-pyrazole-3-carbothioamide, (Compound 4, prepared as described in applicants' copending U.S. patent application Ser. No. 08/418,680, entitled "PESTICIDAL 1-ARYLPYRAZOLE-3-THIOCARBOXAMIDES" [Attorney Docket No. 022650-284 (PH95008)], filed concurrently herewith, incorporated by reference herein in its entirety and relied upon) and a few crystals of 18-crown-6 in 30 milliliters of dry tetrahydrofuran, was added 0.27 gram (0.00244 mole) of potassium tertiary-butoxide, and the mixture was strirred for a few minutes. A 0.16 milliliter (0.00264 mole) portion of methyl iodide was then injected into the reaction mixture, followed by stirring for a two-hour period. An additional 0.08 milliliter (0.0013 mole) portion of methyl iodide and 0.09 gram of potassium tertiary-butoxide were added and stirring was continued for a period of 17 minutes. The mixture was neutralized by passing in gaseous CO2 for about 10 minutes and volatiles were then removed under reduced pressure. The residue was taken up in dichloromethane and filtered, and the filtrate was evaporated to give the product as a crude residue. This was chromatographed on silica, eluting with 2:1 ethyl acetate/hexane, followed by a second chromatography employing 4:1 chloroform/acetone as the solvent, resulting in 0.67 gram (0.00155 mole) of 5-amino-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-methylsulfinyl-1H-pyrazole-3-carboximidothioic acid methyl ester (99.2% purity) having a melting point of 206.5° C. This compound is referred to hereinafter as Compound 2.

Provenance & Evidence